The present invention relates to tools that limit the amount of torque delivered by the tool and, specifically, tools that limit the amount of torque and incorporate a ratcheting mechanism into the tool. Most specifically, the present invention relates to torque limiting and ratcheting tools that are used for in medical procedures.
Many mechanical devices are used to deliver a large amount of torque to a screw, bolt, nut, or other similar device or object. Even though there is a large amount of torque being delivered, in many situations, it is still desirous to control the precise amount of torque being delivered. For instance, too much torque may strip the object that is being driven, which would lead to the driven object becoming ineffective, such as a stripped bolt or screw. This is especially important in medical operations and procedures, where precision is critical, such as when working with spinal and skeletal structures and related devices. Thus, drivers have been developed to limit the amount of torque delivered to the driven object or device.
Devices that deliver a limited amount of torque are generally mechanically limited in other precise functions that may be carried out with the device. For example, devices that limit the amount of torque delivered by the device and also incorporate ratcheting arrangements have limited precision. Because the individual components of the torque assembly are interacting with the components of the ratcheting portion of the tool, precision is less than ideal for both of these functions, especially after repeated uses of the device.